Display apparatus for automotive vehicle

ABSTRACT

In a display apparatus for an automotive vehicle including a projector disposed at the ceiling of the automotive vehicle to project display images and a half mirror for reflecting projected display images to the driver, an angular position of the half mirror surface from the lateral direction of the vehicle is automatically adjusted according to vehicle lateral acceleration. Therefore, the driver can appropriately see virtual display images ahead of the half mirror along the driver&#39;s eye direction variable according to vehicle lateral acceleration.

This is a continuation of co-pending application Ser. No. 07/151,632filed on Feb. 3, 1988, now U.S. Pat. No. 4,837,551.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a display apparatus for anautomotive vehicle and more specifically to a head up display apparatusby which the driver can see display images projected from a projectorand reflected from a reflector disposed in front of the windshield, asvirtual images, in superimposition upon the outside view through thewindshield.

2. Description of the Prior Art

The same applicant has recently proposed a novel head up displayapparatus for an automotive vehicle which comprises a projector disposedat a ceiling of the automotive vehicle to project display images and ahalf reflector disposed on a dashboard of the vehicle to reflect thedisplay images projected by the projector and to transmit the outsideview to the driver, simultaneously. The half reflector is a half mirroror a hologram plate. The above display apparatus can provide stabledisplay images without being subjected to external sunlight, being freefrom dimensional restriction due to small dashboard inside space andhigh in heat radiation efficiency.

In the above display apparatus, although the half reflector is designedso that the size becomes as small as possible, when the half reflectoris disposed in front of the driver, since the frontward field of visionis obstructed, the presence of the half mirror is not preferable from astandpoint of safety in driving a vehicle.

To overcome this problem with safety, the half reflector is preferablydisposed on the dashboard being a little dislocated from the driver'sfront toward the longitudinal vehicle center. In the above-mentionedarrangement of the half reflector, however, there still exists a problemin that the driver cannot appropriately see display images reflectedfrom the half reflector when the driver's body is tilted inward oroutward due to vehicle running along a sharp curved road or when thedistance between the driver and the half reflector differs according todriver's physique.

The above-mentioned problems will be described in further detailhereinafter with reference to the attached drawings under DETAILEDDESCRIPTION OF THE PREFERRED EMBODIMENTS.

SUMMARY OF THE INVENTION

With these problems in mind, therefore, it is the primary object of thepresent invention to provide a display apparatus for an automotivevehicle including a projector and a half mirror, in which an angularposition of the half mirror surface from the lateral direction of thevehicle can be automatically adjusted according to vehicle lateralacceleration so that the driver can appropriately see virtual displayimages ahead of the half mirror along the driver's eye directionvariable according to vehicle lateral acceleration.

To achieve the above-mentioned object, a display apparatus for anautomotive vehicle according to the present invention comprises: (a)projecting means, disposed in a passenger compartment of the automotivevehicle, for projecting display images; (b) half mirror reflecting meansfor reflecting the display images projected by said projecting means toa driver; (c) actuator means, coupled to said half mirror reflectingmeans, for turning said half mirror reflecting means to adjust anangular position of a reflection surface of said half mirror reflectingmeans from a lateral direction of the vehicle; (d) sensor means fordetecting a change in vehicle travel direction; and (e) control means,coupled to said actuator means and said sensor means, for controllingthe angular position of said half mirror reflecting means according tovehicle lateral acceleration detected by said sensor means toautomatically form virtual display images ahead of said half mirrorreflecting means in a driver's eye direction variable according tovehicle lateral acceleration.

Further, it is preferable to provide another actuator means, coupled tosaid half mirror reflecting means, for tilting said half mirrorreflecting means to manually adjust a tilt angle of said half mirrorreflecting means so that display images can be correctly reflected fromsaid half mirror reflecting means to the driver according to a driver'ssitting height.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the display apparatus for an automotivevehicle according to the present invention will be more clearlyappreciated from the following description of the preferred embodimentsof the invention taken in conjunction with the accompanying drawings inwhich like reference numerals designate the same or similar elements orsections throughout the figures thereof and in which:

FIG. 1(A) is a diagrammatical top view for assistance in explaining aproblem involved in a display apparatus for an automotive vehicle;

FIG. 1(B) is a diagrammatical side view of the display apparatus shownin FIG. 1(B).

FIG. 1(C) is another diagrammatical top view for assistance inexplaining another problem involved in the display apparatus for anautomotive vehicle;

FIG. 2 is an enlarged diagrammatical side view, including a blockdiagram, showing an embodiment of a display apparatus for an automotivevehicle according to the present invention;

FIG. 3 is a partial front view of the display apparatus shown in FIG. 2;

FIG. 4 is an illustration showing an operation panel of the apparatusshown in FIG. 2;

FIG. 5(A) is an illustration for assistance in explaining the driver'sbody inclination when the vehicle is running along a sharp curved road.

FIG. 5(B) is a diagrammatical top view for assistance in explaining thedriver's head position when the vehicle is running along a sharp curvedroad; and

FIG. 6 is a diagrammatical top view for assistance in explaining thedriver's head position when the vehicle is running along another sharpcurved road.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1(A) and (B) show a display apparatus for an automotive vehicledisclosed in the copending application filed by the same applicant. Inthe drawings, the display apparatus comprises a half reflector unit 3disposed on a dashboard 5 in front of a windshield 2 of an automotivevehicle 1 and a projector unit 9 attached to a ceiling of the vehicle 1.The half reflector unit 3 is a half mirror, for instance, havingappropriate reflectivity and transmissivity. The projector unit 9 ismade up of a display device 6 for displaying various information such asvehicle speed, for instance, related to the vehicle, an optical element7 such as convex lens, for instance, for projecting display images tothe reflector unit 3, and a casing 8 for housing the display device 6and the optical element 7. In this display apparatus, a virtual image 6Ais focused at a position about 10 m away from the eye 4A of the driver 4and ahead of the windshield 2 of the vehicle 1, for instance, as shownin FIG. 1(B). Therefore, the driver 4 can see display images projectedfrom the projector unit 9 and reflected from the reflector unit 3 about10 m ahead of the driver's eye 4A in superimposition upon the outsideview.

Although the size of the half reflector unit 3 is minimized, since thereflector unit 3 is disposed in front of the driver 4, there exists aproblem in that the driver's field of vision is obstructed and thereforethe reflector unit 3 is not preferable from a standpoint of safety indriving the vehicle.

The above-mentioned problem can be solved by disposing the halfreflector unit 3 on the dashboard 5 at a position a little dislocatedfrom the driver's front to the vehicle center as shown in FIG. 1(C), andthe projector unit 9 at the ceiling of the vehicle. In an example shownin FIG. 1(C), when the driver 4 is correctly positioned as shown bysolid lines in FIG. 1(C), he can see display images 6A projected by theprojector unit 9 and reflected from the half reflector unit 3. However,when the position of the driver 4 is dislocated as shown by the dashedlines in FIG. 1(C), as when the vehicle is running along a sharp curvedroad or when the driver takes a seat out of the center thereof due tothe driver's habit of seating, there exists another problem in that thedriver 4 cannot correctly recognize display images reflected from thehalf reflector unit 3.

In view of the above description, reference is now made to an embodimentof the display apparatus for an automotive vehicle according to thepresent invention.

In FIGS. 2 and 3, the display apparatus comprises roughly a half-mirrorreflector unit, a projector unit, and a control section. Further, thereflector unit is automatically turned adjustably rightward or leftwardto adjust an angular position of a surface of the half mirror reflectorunit from a lateral direction of the vehicle under control of thecontrol section according to vehicle lateral acceleration and manuallytilted upward or downward to adjust a tilt angle of the half mirrorreflector unit according to the driver's sitting height.

In FIG. 3, a square half-mirror reflector unit 3 is formed with twopivotal axles 3a and 3b each projecting from the lower side portionthereof. These two pivotal axles 3a and 3b are inserted into bearingholes 10c and 10d respectively formed at a pair of support arms 10a and10b of the support member 10 to pivotably support the reflector unit 3by the support member 10.

This support member 10 is formed with a projecting rotary shaft 10e atthe lower middle portion thereof. This rotary shaft 10e is inserted intoa bearing hole 5a formed vertically in the dashboard 5 so as to bepivotably supported, and retained by a retainer ring 12 engaged with therotary shaft 10e from the inside of the dashboard 5. The pivotal axle 3bis connected to an actuator such as a motor 11 disposed coaxially withthe bearing hole 10d of the support arm 10b in order to tilt thereflector unit 3 upward or downward.

Further, the rotary shaft 10e is connected to another actuator such as amotor 13 for turning (pivoting) the reflector unit 3 rightward orleftward to adjust an angular position of a surface of the half mirrorreflector unit 3 from the lateral direction of the vehicle. The motor 13is fixed to a support plate 14 fixed to the inside of the dashboard 5.

In FIG. 2, the control section includes a first motor driver 16, asecond motor driver 15, a controller 17, a lateral acceleration sensor18, and an operation panel 19. The first motor driver 16 is connected tothe first actuator 13 and the second motor driver 15 is connected to thesecond actuator 11. The driver 16 is operated under control of thecontroller 17 to rotate the motor 13 in the forward or reversedirection. The lateral acceleration sensor 18 detects the direction(rightward or leftward) and magnitude of lateral vehicle acceleration orcentrifugal force applied to the vehicle when the vehicle is runningalong a sharp curved road and generates a signal corresponding thereto.The operation panel 19 disposed on the surface of the dashboard 5includes an auto/manual selector button (A/M) 19a, an auto indicatorlamp (AUTO) 19f, a reflector turn-rightward button (TURN RIGHT) 19b, areflector turn-leftward button (TURN LEFT) 19c, a reflectortilt-downward button (TILT DOWN) 19d, and a reflector tilt-upward button(TILT UP) 19e, as depicted in FIG. 4.

Further, although not shown, there is provided an angular positionsensor for detecting an angular position of a surface of the half mirrorreflector unit 3 from a lateral direction of the vehicle.

Furthermore, the controller 17 stores a table which lists preferableangular positions of the reflector unit 3 according to detected vehiclelateral accelerations.

On the other hand, at the ceiling la of the vehicle 1, a projector unit9 is fixed so as to project display images to the reflector unit 3.

The operation of the display apparatus of the present invention will bedescribed hereinbelow: when the auto/manual selector switch 19a is setto auto and therefore the auto indicator lamp 19f comes on, the vehicleacceleration sensor 18 applies a vehicle acceleration signal to thecontroller 17 when accelerated. In response to this acceleration signal,the controller 17 selects predetermined data indicative of anappropriate angular position of the reflector member 3 dislocated fromthe lateral direction of the vehicle in accordance with table look-upmethod, and generates a control signal to the actuator driver 16 on thebasis of the selected data. Therefore, the reflector unit 3 isadjustably turned to an appropriate angular position according to thedetected vehicle acceleration, until the selected data matches anangular position detected by the angular position sensor (not shown)provided for the actuator 13. In the above-mentioned operation, thereflector unit 3 is controlled to a target angular position selectedfrom a look-up table in response to the feedback value of the angularposition sensor by feedback control method. Without being limitedthereto, however, it is also possible to control the reflector unit 3 toa target angular position selected from a look-up table by directforward control method. In this direct control method, the actuator suchas a step motor 13 is directly moved to the target position withoutproviding the above-mentioned angular position sensor (not shown).

FIG. 5(A) shows an example where the vehicle 1 is running along aleftward curved road. In this case, since a rightward lateralacceleration is applied to the vehicle or the driver due to acentrifugal force applied to the vehicle or the driver, the driver 4automatically tends to tilt his body in the leftward direction, as shownby the solid lines in FIG. 5(B). In the display apparatus of the presentinvention, however, since the reflector unit 3 is turned in therightward direction (clockwise in FIG. 5(B)) according to the appliedvehicle acceleration direction and magnitude detected by the sensor 18,it is possible to appropriately reflect the display images projectedfrom the projector unit 9 toward the driver 4. In the above automaticangular position adjustment of the reflector unit 3, the reflector unit3 is pivoted in the rightward direction (clockwise) by an angle θ_(R)selected from a look-up table on the basis of the detected lateralacceleration value.

Similarly, FIG. 6 shows an example where the vehicle 1 is running alonga rightward curved road. In this case, since a leftward lateralacceleration is applied to the driver, the driver automatically tiltshis body in the rightward direction as shown, so that the reflector unit3 is turned in the leftward direction (counterclockwise in FIG. 6) by anangle θ_(L) selected from a look-up table on the basis of the detectedlateral acceleration value.

On the other hand, when the auto/manual selector switch 19a is set tomanual and therefore the auto indicator lamp 19f goes off, the reflectorunit 3 can be turned rightward or leftward or tilted upward or downwardby depressing the buttons 19b to 19e, irrespective of vehicle lateralacceleration, so that the driver can adjustably move the reflector unit3 in manual operation. In particular, the driver can adjust thereflection direction of the reflector unit 3 according to the driver'ssitting height by depressing the buttons 19d and 19e to tilt thereflector unit 3 upward or downward so as to correctly face the driver4.

In the above description, the projector is disposed at a ceiling of theautomotive vehicle. However, without being limited thereof, it ispossible to dispose the projector at an appropriate position within thepassenger compartment by use of appropriate optical means, wherenecessary.

Further, in the above description, the vehicle lateral accelerationsensor is explained by way of example. However, without being limitedthereto, it is possible to utilize various sensors which can detect achange in vehicle travel direction such as a steering wheel angularposition sensor.

As described above, in the display apparatus of the present invention,since the reflector unit can be automatically turned rightward orleftward according to a detected vehicle lateral acceleration, thedriver can appropriately see the display images projected by theprojector unit and reflected by the reflector unit, even if the driver'sbody is tilted in either direction when the vehicle is running along asharp curved road, thus improving the driving safety and displayrecognizability simultaneously. Further, the tilt angle of the halfmirror reflector unit is adjustable manually according to the driver'ssitting height.

What is claimed is:
 1. A display apparatus for an automotive vehiclecomprising:(a) projecting means, disposed in a passenger compartment ofthe automotive vehicle, for projecting display images; (b) half mirrorreflecting means for reflecting the display images projected by saidprojecting means to a driver; (c) actuator means, coupled to said halfmirror reflecting means, for moving said half mirror reflecting means toadjust a position of a reflection surface of said half mirror reflectingmeans from at least a lateral direction of the vehicle; (d) sensor meansfor detecting a change in vehicle lateral acceleration; and (e) controlmeans, coupled to said actuator means and said sensor means, forcontrolling the position of said half mirror reflecting means accordingto vehicle lateral acceleration detected by said sensor means toautomatically form virtual display images ahead of said half mirrorreflecting means in a driver's eye direction variable according tovehicle lateral acceleration.
 2. The display apparatus for an automotivevehicle, as set forth in claim 1, which further comprises anotheractuator means, coupled to said half mirror reflecting means, fortilting said half mirror reflecting means to manually adjust a tiltangle of said half mirror reflecting means so that display images can becorrectly reflected from said half mirror reflecting means to the driveraccording to a driver's sitting height.
 3. The display apparatus for anautomotive vehicle, as set forth in claim 1, wherein said control meanscontrols said half mirror reflecting means in accordance with tablelook-up method on the basis of detected vehicle lateral acceleration. 4.The display apparatus for an automotive vehicle, as set forth in claim3, wherein said control means controls said half mirror reflecting meansin direct forward control method.
 5. The display apparatus for anautomotive vehicle, as set forth in claim 3, wherein said actuator meanscomprises a sensor for detecting an angular position of a reflectionsurface of said half mirror reflecting means to control said half mirrorreflecting means in feedback control method.
 6. A display apparatus foran automotive vehicle having a passenger compartment and a driver,comprising:(a) projecting means disposed in the passenger compartment ofthe automotive vehicle, for projecting display images; (b) half-mirrorreflecting means having a reflection surface for reflecting the displayimages projected by said projecting means to a driver; (c) actuatormeans coupled to said half-mirror reflecting means, for moving saidhalf-mirror reflecting means to adjust a position of a reflectionsurface of said half-mirror reflecting means from at least a lateraldirection of the vehicle; (d) sensor means for detecting vehicle lateralacceleration; and (e) control means coupled to said actuator means andsaid sensor means, for controlling the position of said half-mirrorreflecting means in accordance with a look-up table of values on thebasis of detected vehicle lateral acceleration detected by said sensormeans to automatically form virtual display images ahead of saidhalf-mirror reflecting means in a driver's eye direction variableaccording to vehicle lateral acceleration.
 7. The display apparatus foran automotive vehicle, as set forth in claim 6, wherein said controlmeans controls said half-mirror reflecting means by direct forwardcontrol.
 8. The display apparatus for an automotive vehicle, as setforth in claim 6, wherein said actuator means comprises a sensor fordetecting an angular position of a reflection surface of saidhalf-mirror reflecting means to control said half-mirror reflectingmeans by feedback control.